Complex coefficient microwave photonic filter based on multiwavelength phase modulation and PM-to-AM conversion

An incoherent complex coefficient microwave photonic filter based on multiwavelength phase modulation and a high birefringence fiber loop mirror (Hi–Bi FLM) is proposed and successfully demonstrated. A multiwavelength erbium-doped fiber laser (EDFL) provides multiple taps, while the Hi–Bi FLM performs phase modulation (PM) to amplitude modulation (AM) conversion. Taps with positive, negative, or complex coefficients can be generated by control of the multiwavelength input at different positions of the Hi–Bi FLM response with positive and negative slopes. As a result, microwave photonic filter with positive, negative, or complex coefficients has been achieved by adjustment of the EDFL output.

► Microwave photonic filter with positive, negative, or complex coefficients has been achieved.
► The taps are provided by multiwavelength erbium-doped fiber laser.
► A high birefringence fiber loop mirror (Hi-Bi FLM) performs phase modulation to amplitude modulation conversion.
► Coefficients can be controlled by adjustment of the multiwavelength input at different positions of the Hi-Bi FLM.